Modern motor vehicles often comprise speech processing systems that enable the voice control of vehicle functions. The quality of the speech recognition is affected by external noise. A particular challenge for the speech recognition is sudden changes of the driving noise such as occur when driving over unevennesses in the road such as, for example, humps or potholes or in the event of changes of the surface structure of the road.
U.S. Pat. No. 7,725,315 B1 discloses a method, with which temporary driving noise originating from the road is identified using characteristic signal properties and can be distinguished from speech signals. Suitable signal characteristics are for example pairs of time-related sound events, if first the front wheels and then the rear wheels pass an unevenness of the road, and other characteristic time profiles of signal strengths and frequencies. For better recognition of temporary driving noise, different temporal and spectral characteristics of temporary driving noise are modelled and compared with the just acquired microphone signal.